This invention relates to an extensible handle bar for tools which comprises two telescoped tubes. On the outer tube, a sleeve-shaped body consisting of thermoplastic material and being provided with an external thread is firmly mounted, a said body having an extension provided with longitudinally extending slots and an external taper and extending beyond the trailing end of the outer tube, a sleeve-shaped threaded nut being guided on the body and being provided with an internal taper cooperating with the external taper of the body for the purpose of clamping the inner tube of the handle bar.
Such handle bars are know and are, for example, used for cleaning tools as brushes, sponges or the like or for tools for applying for instance paint, in order to be able to perform cleaning or painting work located at high levels from the ground or floor.
In the known handle bars, however, a safe connection of the two tubes of the handle bar is not guaranteed, as practice has shown.
There is already known an extensible handle bar (German Offenlegungsschrift No. 31 22 103) in which the body, provided with an external thread, comprises at its circumference a plurality of radially arranged extensions having the shape of longitudinal arms, being prestressed and comprising at the back sides of their free ends thickened portions with which the arms pass through cutouts in the wall of the tube carrying the body. The sleeve-shaped threaded nut which is guided on the external thread of the body forms an internal taper adjacent to its thread by means of which the thickened portions of the arms of the body are radially pressed against the wall of the inner tube when the threaded nut is screwed unto the body provided with an external thread. This clamping of the inner tube is, however, not sufficient, as practice has shown, in order to avoid an unintended shifting of the inner tube. Furthermore, it is rendered difficult to exchange the body provided with an external thread in the case of wear, for example, because the resilient arms of the body must be disengaged from the cutouts in the wall of the tube, which is possible only by means of a suitable tool. Such a tool, however, is in most cases not readily available for the user of the handle bar.
There is further known an extensible handle bar (German Offenlegungsschrift No. 33 17 270) in which an annular wedge-type sleeve is clampable between the sleeve-shaped body provided with external threads and mounted on the outer tube and the inner tube. By tightening the sleeve-shaped threaded nut guided on the body provided with external threads, the wedge-type sleeve is moved, for the purpose of clamping the inner tube, into the space between said inner tube and the body provided with external threads or, in the inverse case, moved out of the space between the body provided with external threads and the inner tube for the purposes of loosening said inner tube. Besides the fact that this arrangement needs a further element, i.e. the wedge-type sleeve, in addition to the body provided with external threads and the sleeve-shaped threaded nut, also in this clamping arrangement the clamping of the inner tube is effected in an unsufficient manner by means of a wedge-shaped surface.